JP2935079B2 - XID compatible transparent remote MAC bridge device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an ISO 8802-2
XID-compatible transparent remote MAC that can relay duplicate address check control frames based on XID commands / responses specified by LLC type I
Related to bridge devices.

[0002]

2. Description of the Related Art A transparent remote MAC bridge device is an intermediate device between LANs for interconnecting a plurality of remote LANs via a wide area network. FIG.
2 shows an outline of functions of the transparent remote MAC bridge device. The transparent remote MAC bridge device uses the address processing function of the MAC layer to diagnose all received frames, updates the filtering database from the source MAC address of the frame, and updates the filtering database and the destination of the received frame. It has a function of comparing the MAC address with the MAC address to determine whether the frame should be relayed or discarded, and when relaying, to which port the frame should be transmitted. Hereinafter, this function is referred to as “filtering”. FIG. 4 shows the internal configuration of the transparent remote MAC bridge device. The LAN port is an interface for connecting a LAN trunk. The wide area network ports 1 and 2 are wide area network interfaces for connecting a wide area network. The MAC entity controls transmission and reception of frames. The MAC relay entity also controls the updating of the filtering database and the above-mentioned filtering. Regarding this, JIS X 5003-1987 S018 (V1.0)
You can refer to the description in the MAC Bridge Implementation Rules (published by the Japan Standards Association, created by the Information Processing and Interoperability Technology Association).

FIGS. 5 and 7 show a procedure for updating a filtering database (FDB) of a transparent remote MAC bridge device. Updating of the filtering database is performed by a learning process. The learning process checks the source MAC address of the frame transmitted from each port by receiving the frame, and checks the filter information of the filtering database, that is, the source M
The correspondence between the AC address and the port and the elapsed time since the registration are learned. To explain this in more detail,
It is as follows. Transparent remote MAC
The bridge device receives all frames on the LAN and the wide area network port (step 11). However, transmission error frames including FCS errors are discarded (step 1).
2 and 13). The normal frames that have not been discarded are passed to the filtering database update process (learning process). In the learning process, the above-described check is performed. If the source MAC address is registered in the filtering database, whether the reception port number in which the source MAC address is registered is the same as the port number that received the frame. Check whether it is (steps 14 and 15). If they are the same, the elapsed time since registration is returned to "0", and the process proceeds to the filtering process (step 16). If they are different, the source MA
After changing the reception port number in which the C address is registered to the port number that received the frame, the elapsed time since the registration is returned to "0", and the process proceeds to the filtering process (steps 18 and 19). . On the other hand, if the source MAC address is not registered in the filtering database, the port that has received the frame and the source MAC address of the frame are added to the filtering database, and the elapsed time since the registration is set to “ 0 "
And go to the filtering process (step 14
And 17). When the above learning process is completed, the received frame is sent to the filtering process. The filtering process is a process of determining whether to relay the frame.

FIGS. 6 and 7 show a procedure of a filtering process of a transparent remote MAC bridge device. Filtering is performed by a filtering process. Upon receiving the frame, the filtering process checks the filter information in the above-mentioned filtering database based on the destination MAC address, and selects a port to be forwarded. Queue the frame for all ports selected as forwarding destinations. Frames that cannot be queued to any port are discarded. Each frame transmitted from the filtering process is transmitted from the corresponding port. This will be described in more detail as follows. In the filtering process, the destination MA of the received frame
The C address is checked to see if the same MAC address is registered in the source MAC address of the filtering database (step 20). If the frame has been registered, it is checked whether the reception port number in which the destination MAC address is registered is the same as the port number that received the frame (step 22). If they are the same, the frame is discarded (step 24). If different, the frame is relayed to the receiving port number in which the destination MAC address is registered (step 21). On the other hand, if the same MAC address is not registered in the source MAC address of the filtering database, the frame is relayed to all ports other than the port number that received the frame (steps 22 and 23).

[0005]

The operation flow of the above-mentioned transparent remote MAC bridge device (FIG. 7)
According to the above, in a frame having the same destination MAC address and source MAC address, the port selected as the transfer destination by the filtering procedure becomes the receiving port of the frame, and the frame is discarded. Therefore, the duplicate address check control frame based on the XID command / response specified by ISO 8802-2 LLC type I is discarded because the destination MAC address and the source MAC address are the same.
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to solve the above-described problems in the conventional technology and to provide a duplicate address by an XID command / response defined by ISO 8802-2 LLC type I. An object of the present invention is to provide an XID-compatible transparent remote MAC bridge device capable of relaying a control frame.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to provide a function of interconnecting a plurality of LANs via a wide area network, diagnosing all received frames, and specifying the source address of the frames. In the transparent remote MAC bridge device that updates the filtering database based on the content of the filtering database and compares the content of the filtering database with the destination MAC address of the received frame, and performs filtering, the updating operation of the filtering database is performed. When the destination MAC address is equal to the source MAC address, the XID-compatible transparent remote MAC bridge device is characterized in that a filtering unit is unconditionally provided without performing filtering processing.

[0007]

The XID-compatible transparent remote MAC bridge device according to the present invention comprises:

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an XID frame processing procedure added in the XID-compatible transparent remote MAC bridge device according to one embodiment of the present invention. FIG. 2 is an overall operation flowchart of the XID-compatible transparent remote MAC bridge device according to the present embodiment. In the XID-compatible transparent remote MAC bridge device shown in the present embodiment, as shown in FIGS. 1 and 2, the filtering database update process (learning) in the conventional transparent remote MAC bridge device described with reference to FIGS. It is characterized in that XID frame processing is performed after the process. As described above, the XID frame process is performed after the updating process (learning process) of the filtering database is completed, and is performed in the following procedure.

That is, in step 31, it is checked whether or not the source address and the destination address of the frame passed from the above-described filtering database update process (learning process) are the same. If these addresses are the same, the frame is relayed to all ports other than the receiving port of the frame (step 21). If different, the process immediately proceeds to the above-described filtering process.
With this, the conventional transparent remote MAC
ISO 8802-2, impossible with a bridge device
It is possible to relay a duplicate address control frame by an XID command / response specified by LLC type I. The above embodiment is an example of the present invention, and it goes without saying that the present invention is not limited to this.

[0010]

As described above in detail, according to the present invention, an XID-compatible transparent remote MAC capable of relaying a duplicate address control frame based on an XID command / response defined by ISO 8802-2 LLC type I This has a remarkable effect that a bridge device can be realized.

[0011]

[Brief description of the drawings]

FIG. 1 is a diagram showing an XID frame processing procedure of an XID-compatible transparent remote MAC bridge device according to an embodiment of the present invention.

FIG. 2 is an operation flowchart of an XID-compatible transparent remote MAC bridge device according to the embodiment;

FIG. 3 is a diagram showing an outline of functions of a general transparent remote MAC bridge device.

FIG. 4 is a diagram showing an internal configuration of a general transparent remote MAC bridge device.

FIG. 5 is a diagram showing a procedure for updating a filtering database of a general transparent remote MAC bridge device.

FIG. 6 is a diagram showing a filtering procedure of a general transparent remote MAC bridge device.

FIG. 7 is an operation flowchart of a general transparent remote MAC bridge device.

[Explanation of symbols]

 21 to 24 and 31: Processing steps

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Claims (1)

(57) [Claims] 1. A function of connecting a plurality of LANs to each other via a wide area network, diagnosing all received frames, updating a filtering database based on a source address of the frames, and In the transparent remote MAC bridge device that performs filtering by comparing the content of the received frame with the destination MAC address of the received frame, the destination MAC address of the received frame is equal to the source MAC address following the operation of updating the filtering database. An XID-compatible transparent remote MAC bridge device, characterized in that a control means for performing unconditional relaying without performing filtering processing is provided in such a case.